Armature support for four pole loud speakers



Juiy 12, 1932, KUNZE 1,867,160

ARMATURE SUPPORT FOR FOUR-POLE LOUD SPEAKERS Filed March 13, 1931 IN TOR WAL X01721.

A'ITQRNEY Patented July 12, 1932 UNITED STATES PATENT OFFICE.

WALTER KUNZE, OF BERLIN, GERMANY, ASSIGNOR TO RADIO CORPORATION OF AMERICA, A CORPORATION OF DELAWARE ARMATURE SUPPORT FOR FOUR POLE LOUD SPEAKERS Application filed March 13, 1931, Serial No. 522,493, and in Germany June 21, 1930.

This invention relates to loud speaker motors. More particularly it relates to a method of supporting the springs on which the armature of the motor is mounted.

a The invention is. disclosed in the accompanying drawing in which Fig. 1 is a plan view of the'armature; Fig. 2 is a side view of the armature and springs; Fig. 3 is a View showing the present method of support- 19 ing the armature springs; Fig. 4 is a view showing the improved method of supporting the armature springs; and Fig. 5 is a view at right angles to Fig. 4.

In the so-called four pole loudspeaker systerns known in the prior art, an armature 1 supported at both ends in a way as shown in Fig. 1 oscillates about the axis AA out of the plane of the drawing. The armature, as shown in Fig. 2, is associated at both ends with the bearing pedestals by means of thin leaf springs 2 so that twisting of these springs is liable to occur as the armature oscillates. Fig. 3 shows the details of the mounting of the armature. The leaf springs are screwed fast with the interposition of suitably dimensioned metal pieces upon small blocks. Now, since the position of the armature in reference to the pole shoes must be exactly adjusted, while, on the other hand the said so leaf springs can not always be fastened with rivets so that they will be exactly at right angles of the plane laid through the armature, not to mention the fact that they may not be exactly level, the exact adjustment of 85 the armature in relation to the pole-shoes must be effected tentatively by interposing pieces 4 of different thickness. This work, as is known from practical experience, requires much time and labor, not to speak of the experience and a good ear that are required therefor inasmuch as satisfactory adjustment is determinable only by the quality of reproduction (tone quality) of the finished loudspeaker. p y

Now the present invention discloses a considerable simplification of this mounting and adjusting work.

Referring to Fig. 4 leaf type springs of the same form have been riveted as before mentioned upon the armature, but the washer or spacer pieces 4 which are also required in this case, are firmly attached and united to the springs by riveting. The armature is then fitted between the pole shoes with spacer pieces which have exactly the size of the required air gap, and pole shoes and armature are kept under pressure. In this arrangement the spacer pieces or interposition means riveted on the leaf springs Wlll' extend into suitable cavities 7 in the supporting blocks 6, no the said recesses being so shaped that the supporting springs and interposition means will not touch the supporting blocks 6 under any circumstances. The armature must be properly fitted in this-position between the pole shoes free from biasing tension. The hollow spaces in the supporting blocks 6 are then filled by a material melting preferably at a low temperature such as soft solder or Woods alloy. This will result in a rigid 7o abutting of the armature supporting means without any change in the adjustment of the armature and in the biasing tension. After the compound or alloy has solidified the spacers between armature and pole shoes 7 are removed and the loudspeaker armature is accurately mounted.

What I claim is:

1. Apparatus for the interconversion of mechanical vibrations and electrical oscilgo lations comprising pole pieces, an armature interposed between said pole pieces, a spring on said armature, supporti'ng members for the ends of said spring, and a material of low melting point surrounding the ends of said 35 spring in said supporting member.

2. In apparatus for the interconversion of mechanical vibrations and electrical oscillations, including pole pieces, a spring supported armature, and supporting members having hollow spaces for the ends of said spring, the method of arranging and supporting said armature between said pole pieces which consists in positioning said armature between said pole pieces by means of removable spacer blocks so that the ends of said spring are in the hollow spaces in said supporting members, in filling said hollow spaces with a molten material having a low melting po1nt,.and inpermitting said molten material to harden-in said hollow Spaces to thus support said spring.

3. In apparatus for the interconversion of mechanical vibrations and electrical oscillations, a body adapted to be vibrated, supporting means for said body, said supporting means permitting vibration of said body, and securing means for said supporting means, the said securing means consisting of congealed, low fusion materialengaging portions of said supporting means.-

4. In apparatus for the-interconversion of mechanical vibrations and electrical variations, the combination of'a body adapted to be vibrated, a lural'ity of spring members connected to sald body for supporting said body in a manner such as to permit vibration thereof, and, means for securing the ends of said springs comprising pockets containing low fusion material congealed around the ends of said springs.

WALTER KUNZE. 

